SMD470110102018 ASSIGNMENT 2 QUESTION 1 15 Marks a Mortar us

SMD4701/101/0/2018 ASSIGNMENT 2 QUESTION 1 (15 Marks) a Mortar used in masonry construction can be described in various classes, uses and mix designs. Justify the statement. 2 Marik b) It is important to know the thermal and moisture coefficients of masonry units. Explain why and state how the information is used in design. 2 MareS c)State in a tabular format the various types of wall ties used for joining two skins of a cavity wall and describe their functions. d) In designing of masonry walling several considerations are taken into account including accommodation of movements. Explain concisely how movements in structural masonry design are accounted for 2 MareS e e effective height and length of a masonry member subjected to axial load is influenced by the degree of lateral support that may be provided. SANS 10164 -1 defines the degree of resistance to lateral movement as either \"simple or \"enhanced\" depending on the construction detail adopted. Explain the difference between \"simple\" and \"enhanced\" resistance and sketch, 2 each, typical construction details showing examples of both types of restraint 5 Marie QUESTION 2 (o Marks) a) A industrial masonry warehouse is located in the province of Western Cape, South Africa. The area is fully developed and it is 500 m above sea level. The building is 7.5 m wide and 22.0 m long. The height of the building to eaves level is 3500 mm and the roof pitch is 15. The walling of the structure must conform to the requirement as set out in SANS 10400: Part K-walling. The walls consist of 220 mm thick burnt clay face brick units. The wall supports a metal sheeted roof on braced timber trusses, providing simple lateral support for the wall at the top. The trusses are spaced at 1200 mm with 600 mm overhangs Calculate wind load on the structure and determine the critical load combinations at ultimate-limit-states. Mares b What effect does the inclusion of self-weight of a wall has on the design compressive strength of masonry in the design of laterally loaded panel wall

Solution

a)Cement mortar classified as per sans are class1 and class2 ,and in various uses like plastering ,strengthening of existing structure etc,and in various design mixes .it is described in various ways because the mortar used is specified in various ways like MC 22,5 MC 12,5 in the specifications of the item in estimation,based on the specification of the item the mixes is done and based on the propotion mixes the strength is dependent,if the motar class is decided then it can tell that the strength of the member durability,life period is decided,hence it s necessary to classify the various classes of the mortar.

b)the thermal and moisture coefficients of he masonry units are use important in construction of mmasonry units expecially in structures subjected to the more heat like kilns walls in industries ware houses etc,the moisture content in the masonry unitscauses efflorescence which is formed in white patches which causes unaesthetic appearance and also losses the bond between the masonry and the plastering.and the thermal coefficients are used to determine the heat insulation of the masonry units based on that uses of such units inparticular atmosphere.based on the thermal and moisture coefficients only the type of units are used in special works

c)

d)movements considerations in structural masonry design:

movement is due to a number of reasons including:- l Thermal expansion / contraction due to temperature changes l Moisture movement

Creep and structural loading

The effects of chemical changes such as sulphate attack

the consideration of these movement effects is as follows

i)vertical movemen jont spacing

ii)movement joint positions-Features of the building which should be considered when determining joint positions in masonry are:-

1. Short returns in clay masonry

2. Changes in height or external materials

3. Window and door openings

4. Location of wall ties with respect to movement joints

5. Bed joint reinforcement

iii)locating wallties adjacet to the wall joints

iv)bed joint reinforcement

name of the wall tie	uses
butterfly type tie	wallties in every second course is used to connect 290,240mm cavitywalls
modified pwd tie	wall laterally supported by lateral column
single wire tie	for connecting two cavity skins
double triangle type tie	wall laterally supporte by lateral column